Image sensor module, image processing system, and image compression method

3. The image compression method of claim 1, wherein the generating of the virtual reference map includes determining the offset value based on the reference values.

4. The image compression method of claim 1, wherein the first values is a pixel value of a first pixel of a plurality of pixels included in the target pixel group.

5. The image compression method of claim 4, wherein the bitstream includes data indicating the first difference value and the second difference value, and mode information indicating a compression method.

6. The image compression method of claim 5, wherein a number of bits allocated to a region including the first difference value is greater than a number of bits allocated to a region including the second difference values.

7. The image compression method of claim 5, wherein the bitstream further includes additional information indicating a bit shift amount of the data or the offset value.

8. The image compression method of claim 1, wherein the first value is an average value of the pixel values.

10. The image compression method of claim 1, wherein the target pixel group includes four pixels that correspond to the same color and arranged in two rows and two columns.

12. The image sensor module of claim 11, wherein the encoder determines the offset value based on the reference values.

13. The image sensor module of claim 11, wherein the encoder adds a preset offset value to each of the reference values.

14. The image sensor module of claim 11, wherein the encoder encodes the target pixel group by using a differential pulse code modulation (DPCM) method based on the virtual reference map.

15. The image sensor module of claim 11, wherein the encoder generates a plurality of pieces of encoded data by compressing the target pixel group according to the plurality of encoding methods and selects encoded data with a lowest error rate from the plurality of pieces of encoded data as compressed data for the target pixel group.

16. The image sensor module of claim 11, wherein the encoder, generates encoded data by compressing the target pixel group by using an encoding method with a higher priority among the plurality of encoding methods, and compresses the target pixel group by using the first encoding method when an error rate of the encoded data is less than or equal to a reference value.

18. The image processing system of claim 17, wherein the plurality of bitstreams are transmitted from the encoder to the decoder through a camera serial interface based on a mobile industry processor interface (MIPI).

19. The image processing system of claim 17, wherein the encoder compresses the target pixel group by calculating a first difference value between a compensated reference value included in the virtual reference map and a first value of at least one of the pixel values, and calculating a second difference value between the first value and another of the pixel values.

20. The image sensor module of claim 11, wherein the encoder compresses the target pixel group by calculating a first difference value between a compensated reference value included in the virtual reference map and a first value of at least one of the pixel values, and calculating a second difference value between the first value and another of the pixel values.